[cogl/wip/rig: 28/33] Add a COGL_EXT_IN_GLES3 option to specify extensions that are in GLES3

[Robert Bragg <rbragg src gnome org>]

commit acedb395dafe4e2c2897e28eb2ae0cebdfa92fa0
Author: Neil Roberts <neil linux intel com>
Date:   Tue Apr 1 14:54:38 2014 +0100

    Add a COGL_EXT_IN_GLES3 option to specify extensions that are in GLES3
    
    Some features that were previously available as an extension in GLES2
    are now in core in GLES3 so we should be able to specify that with the
    gles_availability mask of COGL_EXT_BEGIN so that GL implementations
    advertising GLES3 don't have to additionally advertise the extension
    for us to take advantage of it.
    
    Reviewed-by: Robert Bragg <robert linux intel com>

 cogl/cogl-feature-private.c            |   16 +++++++++++-
 cogl/cogl-feature-private.h            |    5 +--
 cogl/driver/gl/cogl-util-gl-private.h  |   11 +++++++++
 cogl/driver/gl/cogl-util-gl.c          |   33 +++++++++++++++++++++++++++
 cogl/driver/gl/gl/cogl-driver-gl.c     |   39 +++----------------------------
 cogl/driver/gl/gles/cogl-driver-gles.c |   30 +++++++++++++++++++++++-
 6 files changed, 92 insertions(+), 42 deletions(-)
---
diff --git a/cogl/cogl-feature-private.c b/cogl/cogl-feature-private.c
index 7f75a0c..c5a5167 100644
--- a/cogl/cogl-feature-private.c
+++ b/cogl/cogl-feature-private.c
@@ -53,16 +53,28 @@ _cogl_feature_check (CoglRenderer *renderer,
 {
   const char *suffix = NULL;
   int func_num;
+  CoglExtGlesAvailability gles_availability;
   CoglBool in_core;
 
+  if (driver == COGL_DRIVER_GLES2)
+    {
+      gles_availability = COGL_EXT_IN_GLES2;
+
+      if (COGL_CHECK_GL_VERSION (gl_major, gl_minor, 3, 0))
+        gles_availability |= COGL_EXT_IN_GLES3;
+    }
+  else
+    {
+      gles_availability = 0;
+    }
+
   /* First check whether the functions should be directly provided by
      GL */
   if (((driver == COGL_DRIVER_GL ||
         driver == COGL_DRIVER_GL3) &&
        COGL_CHECK_GL_VERSION (gl_major, gl_minor,
                               data->min_gl_major, data->min_gl_minor)) ||
-      (driver == COGL_DRIVER_GLES2 &&
-       (data->gles_availability & COGL_EXT_IN_GLES2)))
+      (data->gles_availability & gles_availability))
     {
       suffix = "";
       in_core = TRUE;
diff --git a/cogl/cogl-feature-private.h b/cogl/cogl-feature-private.h
index 3349113..7ffef5a 100644
--- a/cogl/cogl-feature-private.h
+++ b/cogl/cogl-feature-private.h
@@ -39,11 +39,10 @@
   ((driver_major) > (target_major) || \
    ((driver_major) == (target_major) && (driver_minor) >= (target_minor)))
 
-/* This is a leftover from when we used to support GLES 1.1, though
- * we may want to use this to differentiate WebGL later */
 typedef enum
 {
-  COGL_EXT_IN_GLES2 = (1 << 0)
+  COGL_EXT_IN_GLES2 = (1 << 0),
+  COGL_EXT_IN_GLES3 = (1 << 1)
 } CoglExtGlesAvailability;
 
 typedef struct _CoglFeatureFunction CoglFeatureFunction;
diff --git a/cogl/driver/gl/cogl-util-gl-private.h b/cogl/driver/gl/cogl-util-gl-private.h
index 0165c81..20d833b 100644
--- a/cogl/driver/gl/cogl-util-gl-private.h
+++ b/cogl/driver/gl/cogl-util-gl-private.h
@@ -79,4 +79,15 @@ _cogl_gl_util_get_texture_target_string (CoglTextureType texture_type,
                                          const char **target_string_out,
                                          const char **swizzle_out);
 
+/* Parses a GL version number stored in a string. @version_string must
+ * point to the beginning of the version number (ie, it can't point to
+ * the "OpenGL ES" part on GLES). The version number can be followed
+ * by the end of the string, a space or a full stop. Anything else
+ * will be treated as invalid. Returns TRUE and sets major_out and
+ * minor_out if it is succesfully parsed or FALSE otherwise. */
+CoglBool
+_cogl_gl_util_parse_gl_version (const char *version_string,
+                                int *major_out,
+                                int *minor_out);
+
 #endif /* _COGL_UTIL_GL_PRIVATE_H_ */
diff --git a/cogl/driver/gl/cogl-util-gl.c b/cogl/driver/gl/cogl-util-gl.c
index f1c1a8d..84cd74c 100644
--- a/cogl/driver/gl/cogl-util-gl.c
+++ b/cogl/driver/gl/cogl-util-gl.c
@@ -146,3 +146,36 @@ _cogl_gl_util_get_texture_target_string (CoglTextureType texture_type,
   if (swizzle_out)
     *swizzle_out = tex_coord_swizzle;
 }
+
+CoglBool
+_cogl_gl_util_parse_gl_version (const char *version_string,
+                                int *major_out,
+                                int *minor_out)
+{
+  const char *major_end, *minor_end;
+  int major = 0, minor = 0;
+
+  /* Extract the major number */
+  for (major_end = version_string; *major_end >= '0'
+         && *major_end <= '9'; major_end++)
+    major = (major * 10) + *major_end - '0';
+  /* If there were no digits or the major number isn't followed by a
+     dot then it is invalid */
+  if (major_end == version_string || *major_end != '.')
+    return FALSE;
+
+  /* Extract the minor number */
+  for (minor_end = major_end + 1; *minor_end >= '0'
+         && *minor_end <= '9'; minor_end++)
+    minor = (minor * 10) + *minor_end - '0';
+  /* If there were no digits or there is an unexpected character then
+     it is invalid */
+  if (minor_end == major_end + 1
+      || (*minor_end && *minor_end != ' ' && *minor_end != '.'))
+    return FALSE;
+
+  *major_out = major;
+  *minor_out = minor;
+
+  return TRUE;
+}
diff --git a/cogl/driver/gl/gl/cogl-driver-gl.c b/cogl/driver/gl/gl/cogl-driver-gl.c
index b87c561..9083ecc 100644
--- a/cogl/driver/gl/gl/cogl-driver-gl.c
+++ b/cogl/driver/gl/gl/cogl-driver-gl.c
@@ -278,39 +278,6 @@ _cogl_driver_pixel_format_to_gl (CoglContext *context,
 }
 
 static CoglBool
-parse_gl_version (const char *version_string,
-                  int *major_out,
-                  int *minor_out)
-{
-  const char *major_end, *minor_end;
-  int major = 0, minor = 0;
-
-  /* Extract the major number */
-  for (major_end = version_string; *major_end >= '0'
-        && *major_end <= '9'; major_end++)
-    major = (major * 10) + *major_end - '0';
-  /* If there were no digits or the major number isn't followed by a
-     dot then it is invalid */
-  if (major_end == version_string || *major_end != '.')
-    return FALSE;
-
-  /* Extract the minor number */
-  for (minor_end = major_end + 1; *minor_end >= '0'
-        && *minor_end <= '9'; minor_end++)
-    minor = (minor * 10) + *minor_end - '0';
-  /* If there were no digits or there is an unexpected character then
-     it is invalid */
-  if (minor_end == major_end + 1
-      || (*minor_end && *minor_end != ' ' && *minor_end != '.'))
-    return FALSE;
-
-  *major_out = major;
-  *minor_out = minor;
-
-  return TRUE;
-}
-
-static CoglBool
 _cogl_get_gl_version (CoglContext *ctx,
                       int *major_out,
                       int *minor_out)
@@ -321,7 +288,7 @@ _cogl_get_gl_version (CoglContext *ctx,
   if ((version_string = _cogl_context_get_gl_version (ctx)) == NULL)
     return FALSE;
 
-  return parse_gl_version (version_string, major_out, minor_out);
+  return _cogl_gl_util_parse_gl_version (version_string, major_out, minor_out);
 }
 
 static CoglBool
@@ -432,7 +399,9 @@ _cogl_driver_update_features (CoglContext *ctx,
     {
       const char *glsl_version =
         (char *)ctx->glGetString (GL_SHADING_LANGUAGE_VERSION);
-      parse_gl_version (glsl_version, &ctx->glsl_major, &ctx->glsl_minor);
+      _cogl_gl_util_parse_gl_version (glsl_version,
+                                      &ctx->glsl_major,
+                                      &ctx->glsl_minor);
     }
 
   if (gl_major < 3)
diff --git a/cogl/driver/gl/gles/cogl-driver-gles.c b/cogl/driver/gl/gles/cogl-driver-gles.c
index a124a35..216677f 100644
--- a/cogl/driver/gl/gles/cogl-driver-gles.c
+++ b/cogl/driver/gl/gles/cogl-driver-gles.c
@@ -214,12 +214,32 @@ _cogl_driver_pixel_format_to_gl (CoglContext *context,
 }
 
 static CoglBool
+_cogl_get_gl_version (CoglContext *ctx,
+                      int *major_out,
+                      int *minor_out)
+{
+  const char *version_string;
+
+  /* Get the OpenGL version number */
+  if ((version_string = _cogl_context_get_gl_version (ctx)) == NULL)
+    return FALSE;
+
+  if (!g_str_has_prefix (version_string, "OpenGL ES "))
+    return FALSE;
+
+  return _cogl_gl_util_parse_gl_version (version_string + 10,
+                                         major_out,
+                                         minor_out);
+}
+
+static CoglBool
 _cogl_driver_update_features (CoglContext *context,
                               CoglError **error)
 {
   unsigned long private_features
     [COGL_FLAGS_N_LONGS_FOR_SIZE (COGL_N_PRIVATE_FEATURES)] = { 0 };
   char **gl_extensions;
+  int gl_major, gl_minor;
   int i;
 
   /* We have to special case getting the pointer to the glGetString
@@ -256,9 +276,15 @@ _cogl_driver_update_features (CoglContext *context,
 
   _cogl_gpc_info_init (context, &context->gpu);
 
+  if (!_cogl_get_gl_version (context, &gl_major, &gl_minor))
+    {
+      gl_major = 1;
+      gl_minor = 1;
+    }
+
   _cogl_feature_check_ext_functions (context,
-                                     -1 /* GL major version */,
-                                     -1 /* GL minor version */,
+                                     gl_major,
+                                     gl_minor,
                                      gl_extensions);
 
   if (context->driver == COGL_DRIVER_GLES2)